The classic would be to start from Seathwaite, in Borrowdale, go up to Styhead Pass, along the Guides Route to Lingmell Col, then up to the Summit, returning along the broad ridge past Broad Crag and Ill Crag and down to Esk Hause, then down to Seathwaite via Grains Gill.
The Wasdale route is shorter, but more of a slog, though you could go up via Sty Head and down via Mickedore, making it more interesting; Eskdale routes are beautiful but very long and the Langdale route -also long- can't easily be varied on the return.